Historically birthing stools have been designed to allow mothers to be in a sitting rather than the standard laying position during birth. This is a more natural and physiologically effective position allowing the mother to push more efficiently thereby reducing the stresses of birth on the mother and infant. In a prior art type of this class of birthing stool, a squatted or seated position is supported by a u-shaped seat at a horizontal angle (parallel to the ground). Another prior art example utilizes an angled u-shaped seat with no two-dimensional or three-dimensional curves (i.e. Birth Works birthing stool produced in South Africa). These prior art examples have the disadvantages of a flat sitting surface which does not accommodate the natural anatomy of the female pelvis. Pressure is therefore not evenly distributed over the gluteal area leading to pressure points and the normal lumbar lordosis (curvature) is not accommodated. This can lead to pain over the ischial tuberosities and lower back.
The World Health Organization encourages the practice of freedom in position and movement throughout labour since use of the upright position among other non-supine positions results in a healthier and less painful delivery. Prior art of this class of birthing stool allow for a single position, squatting or seated, depending on the height of the stool (i.e. Birth Mate birthing stool produced in the Netherlands).
Prior art apparatus consist of a u-shaped seat mounted on three or four legs, or that is attached to the ground by side walls whose bottom side sits flush with the floor along a linear path of contact, generally in a semi-circular form. These disparate and perpendicular points of contact with the ground cause a lack of structural integrity and stability in response to forces contacting the stool at varying angles, instead assuming a standard vertical pressure relatively straight downwards. Thus existing birthing stools are not stable enough to be used as a support for positions in which the laboring mother is leaning on the stool for support either in a kneeling position, or standing with one leg on the stool in a lunging position, both of which carry benefits during the second stage of labor and delivery for some. Kneeling is an ideal position in the first stage of labour, helping with the strength, frequency and regularity of contractions, which can aid in the successful dilation of the cervix. Kneeling, or standing with one foot raised in a lunging position (also called the stork position for birthing) with the upper body leaning forward also helps the progression of labour during the second stage. Many women also find that kneeling reduces pain during delivery.
Currently in some hospitals, regulations do not allow for delivery outside of the hospital bed. The instability of prior art apparatus does not allow for existing birthing stools to be used on a bed, which is at times desirable, allowing the facilitation of more effective birthing positioning while adhering to standard hospital regulations.
Due to individual differences in height, as well as individual preferences for the angle of the legs, pelvis, and back in a seated or squatting position during labor and delivery, no single height can be ideal for all, or even most, expectant mothers. No prior art apparatus facilitate a seated or squatted position at varying heights.
Many prior art examples are made of wood which do not allow for adequate cleansing and disinfection of the bodily fluids involved in childbirth. One prior art example is made of fiberglass which allows for cleansing and disinfection, however mechanically attached handles create crevices into which bodily fluids can become trapped (Birth Rite birthing stool produced in Australia). Another prior art example is made of plastic which can be disinfected, but does not have any handles or grips.
Exposure to water during labour is a natural and effective method of easing pain for many laboring women. Water births, in which women give birth in a birthing pool or tub are thus becoming an increasingly common practice. The prior art apparatus made of wood cannot be used with water without being subject to warping of the material. Other prior art apparatus made of plastic, fiberglass, and metal, can be used in a shower, but do not allow for submersion underwater for use in a birthing pool or tub. Further to the above regarding disinfection and water submersion, the ability to adequately completely disinfect the device, including all surfaces, not only those in contact with the user's body, becomes exceedingly important in the case of full submersion of the device into the warm water used in a birthing tub or pool. In these circumstances any trace of bodily fluids on the apparatus could contaminate the water, thus coming into intimate contact with the laboring mother and creating the risk of infection.
One prior art stool was exhibited by this inventor in 2005, which demonstrated a stool comprised of compound curves, with a double ridge design, allowing for optimal support of the birthing mother on one ridge, and a second ridge allowing for a second individual to be seated behind the mother during labour and delivery. This prior art model was hand-carved and then finished by hand with the use of fiberglass. This labour intensive method of production did not allow for economic production of the stool. The design was further disadvantaged by organically shaped hollow walls 1-2″ thick, with the top and the bottom of the stool being attached by three organically sloping walls, each approximately equidistant from the next. The spaces between the walls and the entire interior of the stool were thus open and exposed. This complex pattern of thick and hollow walls meant that the stool was buoyant, and any effort to sink the stool by filling the walls with water would mean that the interior of the walls would be inaccessible, and thus impossible to clean and disinfect. Further the volume of water able to be accommodated in the hollowed walls would not be adequate to counteract the buoyancy of the material, meaning that submersion of the stool underwater was not possible by this means.